Weather Averages in Des Moines
In Des Moines, the summers are warm, humid, and wet; the winters are freezing, dry, and windy; and it is partly cloudy year-round. Over the course of the year, the temperature typically varies from 17°F to 86°F and is rarely below -3°F or above 95°F.
The hot season lasts for 3.8 months, from May 25 to September 19, with an average daily high temperature above 76°F. The hottest day of the year is July 20, with an average high of 86°F and low of 68°F.
The cold season lasts for 3.1 months, from November 28 to March 1, with an average daily high temperature below 43°F. The coldest day of the year is January 21, with an average low of 17°F and high of 33°F.
In Des Moines, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.
The clearer part of the year in Des Moines begins around June 8 and lasts for 4.5 months, ending around October 26. On August 26, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 70% of the time, and overcast or mostly cloudy 30% of the time.
The cloudier part of the year begins around October 26 and lasts for 7.4 months, ending around June 8. On February 13, the cloudiest day of the year, the sky is overcast or mostly cloudy 54% of the time and clear, mostly clear, or partly cloudy 46% of the time.
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Des Moines varies significantly throughout the year.
The wetter season lasts 5.6 months, from April 5 to September 25, with a greater than 26% chance of a given day being a wet day. The chance of a wet day peaks at 43% on June 7.
The drier season lasts 6.4 months, from September 25 to April 5. The smallest chance of a wet day is 8% on January 9.
Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation in Des Moines changes throughout the year.
Rain alone is the most common for 11 months, from February 9 to December 26. The highest chance of a day with rain alone is 43% on June 7.
Snow alone is the most common for 1.5 months, from December 26 to February 9. The highest chance of a day with snow alone is 5% on February 3.
To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. Des Moines experiences extreme seasonal variation in monthly rainfall.
The rainy period of the year lasts for 10 months, from February 13 to December 25, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around June 15, with an average total accumulation of 4.5 inches.
The rainless period of the year lasts for 1.6 months, from December 25 to February 13. The least rain falls around January 21, with an average total accumulation of 0.2 inches.
We report snowfall in liquid-equivalent terms. The actual depth of new snowfall is typically between 5 and 10 times the liquid-equivalent amount, assuming the ground is frozen. Colder, drier snow tends to be on the higher end of that range and warmer, wetter snow on the lower end.
As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day of the year. Des Moines experiences some seasonal variation in monthly liquid-equivalent snowfall.
The snowy period of the year lasts for 4.3 months, from November 13 to March 22, with a sliding 31-day liquid-equivalent snowfall of at least 0.1 inches. The most snow falls during the 31 days centered around December 20, with an average total liquid-equivalent accumulation of 0.3 inches.
The snowless period of the year lasts for 7.7 months, from March 22 to November 13. The least snow falls around July 22, with an average total liquid-equivalent accumulation of 0.0 inches.